1998 Gmc Sierra Sl on 2040-cars

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Diesel Power finds the ultimate modified oil-burner

For nine years, Diesel Power magazine has run the Diesel Power Challenge, this year's grindfest being "a week-long torture test that features seven events, nine trucks, 8,000 horsepower, and nearly 15,000 pound-feet of torque." The road to being crowned "the most powerful truck" starts with a dyno run, and then continues through the completion of a CDL-style obstacle course, an eighth-of-a-mile drag race while towing a 10,000-pound trailer, a quarter-mile drag race without a trailer, a fuel economy test in the mountains and finally a sled-pulling test through a 300-foot-long packed-mud pit.
What kind of trucks get into such a fight? Last year's winner, for instance - who upgraded his truck this year to prove he didn't "luck into the win" - drives a 2008 Ford F-250 Super Duty with a 6.4-liter Power Stroke V8 upgraded with a custom intake, Elite Diesel triple turbos and a two-stage nitrous system. Another competitor has a 2005 Dodge Ram 2500 powered by a 5.9-liter Cummins inline-six, upgraded with Garrett turbos, dual-stage nitrous, a seven-inch exhaust stack and twin fans built into the bed to cool the Sun Coast Omega transmission. The numbers on that truck: 1,255 horsepower, and 2,063 pound-feet of torque at the wheels. Naturally, as the image above might suggest, things don't always end well.
You'll find all five videos covering this years challenge below. A scene in the dyno video sums it all up perfectly: a competitor leaves his nitrous on too long and the crew is treated to some ominous poppings, he leans out the window, throws both hands up and shouts, "Amer'ca!"

2015 GMC Yukon Denali

Automotive enthusiasts often wonder aloud - ourselves included - why General Motors would choose to keep GMC while sending Pontiac (and Saturn, and even Oldsmobile before it) into the great automotive graveyard in the sky. The answer, as is so often the case, is profit. It's much easier for GM to rake in money hand over fist by rejiggering the trucks, crossovers and SUVs that it would already be developing for Chevrolet and making them a bit more luxurious and *ahem* "Professional Grade" with new grilles, badges and unique packaging for GMC.
While it may sound like we're being cynical, we totally approve of GM's fullsize SUV strategy. The least-expensive way to get into the fold is with the Chevrolet Tahoe, which starts at $45,595 with a 5.3-liter V8 engine and a cloth interior. Bumping that same Chevy to LTZ trim and its $59,995 sticker price lands a much nicer leather-clad interior and more techno-bells and whistles than you can shake a stick at. But it still looks like a Tahoe, and it still comes with the smaller 5.3-liter engine. Or, you could do what we'd do: Walk into your GMC dealer and take a look at the Yukon Denali. Here's why.
Driving Notes

2014 GMC Sierra Regular Cab revealed

Despite initially launching in just the Crew Cab configuration, the lineup of 2014 GMC Sierra and 2014 Chevrolet Silverado trucks will eventually grow to include three cab sizes and three bed lengths. Oddly enough, our first look at the Regular Cab bodystyle has arrived in a General Motors press release discussing the aerodynamics of the new truck, with an image showing a Sierra Regular Cab testing in the wind tunnel. GMC's website says that Regular Cab and Double Cab models will be available by summer.
While it really didn't take too much imagination to figure out what the two-door version would look like, this Regular Cab Z71 looks pretty sharp with its standard-length (6.5-feet) bed - a longer bed will also be offered. In regards to the aero tuning of the 2014 Sierra, these images show just how far GM has gone in maximizing the truck's fuel efficiency and reducing its noise, vibration and harshness (NVH) levels. Interestingly, the press release shows visual evidence that keeping the tailgate up is best for aero - there's always been some Mythbusters-level contention about such things -but GM also says that adding tonneau covers (preferably soft) and running boards can also help improve the overall aerodynamics. Scroll down for all of this aero info in the official press release.